Compressed air is one of the most critical and expensive utilities in any manufacturing facility. That said, maintenance and monitoring of this crucial system are largely ignored. When it is given attention, the focus is usually in the compressor room. The piping distribution system — where most problems exist — is often ignored. This is a costly mistake. Incorrectly sized piping, leaks, rust, or other undetected issues in the piping distribution system are often the real issue – and quite simple to fix.
To fully manage your compressed air system and pinpoint areas of inefficiency, pressure, humidity, flow, temperature, and power should be measured and monitored.
To identify where to measure the above data points in your facility, a site survey must be done. A site survey is a walkthrough of the facility with a trained professional. The trained professional will ask you questions about the facility and what pain points you have. Using the answers from questions and their observations, the trained professional will provide the recommended mix of sensors and placement locations. If going with a wireless monitoring solution, the site survey will also identify any communication dead zones or obstructions to avoid when installing the sensors.
Every 2 psi of air pressure generated equals 1% of a compressed air system’s total energy cost. Having an inefficient compressed air system could be costing your tens or even hundreds of thousands of dollars in wasted energy. These inefficiencies result from several causes including:
inadequately sized piping,
internal corrosion of the distribution piping,
the wrong sized compressor, and
lack of compressed air storage.
Any of these issues can cause your compressor to work overtime, ultimately shortening its life expectancy.
To identify and address these issues, take pressure readings throughout the compressed air system at key locations in the compressor room, at point of use and throughout the piping distribution system. Your key locations will be identified through the site survey. This will provide a total system pressure profile. Without this holistic approach, you may know that a machine is being starved for air, but will not know where pressure starts to drop — critical information for troubleshooting. Your compressor may be completely adequate for your application, but if you have undersized or corroded piping, adding more compressor capacity isn’t going to help.
You can take these measurements manually with a pressure gauge, but that gives you only a snapshot of the data at a particular point in time. For ongoing information about your system, you can install sensors throughout the system. Wireless sensors reporting to the cloud make this task simple and cost-effective.
Monitoring humidity in your compressed air system provides early detection of system complications. Excess moisture corrodes pipes and damages internal components of machinery, increasing maintenance costs and causing production downtime. In precise manufacturing such as painting applications, excess moisture causes quality control problems in the form of product damage and paint not adhering. Moisture breeds harmful bacteria that contaminate finished goods.
The use of humidity sensors can prevent these issues. By monitoring the humidity in the compressor room lines and point of use, you can confirm your system is operating at peak efficiency. A site survey will identify if additional humidity sensors are needed in your facility. High levels of humidity in your system can indicate either a problem with the dryer, condensate removal system or simply the location of the compressor and dryer.
A common cause of inefficient air systems is clogged piping. Over time, the interior or older steel piping corrodes, restricting the flow of air. Undersized piping also causes inefficiencies in the compressed air system. In most cases, the piping was correct for the original demand, but as the facility grows and demands more air, the piping system becomes too small to deliver the correct air pressure to the point of use.
Leaks also cause compressed air system inefficiencies. Leaks are mainly seen in older pipes, but newer installations can still leak as well. Eventually, threaded connections start to separate, creating a path for air to escape from the distribution network. Installation mistakes will lead to leaks, as well as the potential for serious injuries. When attaching connectors, make sure to assemble the system to the manufacturer’s specifications to avoid leaks and potential injury.
Using the results of your site survey, placing flow sensors at the correct locations in your compressed air system identifies potential leaks, unnecessary or inappropriate uses of compressed air, and the demand of the entire facility and each individual department. The best way to check for system leaks is to monitor the artificial demand of air during idle (no production) times. The higher the artificial demand, the more leaks exist in the system. Analyzing the data also determines the health of the piping. The interior of pipes will corrode and create blockages without ever showing signs on the outside. An area with poor flow readings means the pipe has begun to corrode.
Monitoring the temperature determines the health of your compressor room equipment. To monitor the health, temperature sensors should be placed right after the key components (e.g. compressor, dryer, and storage tanks). Comparing the temperature readings to the optimal performance bands provides a quick check on the performance of the equipment. If the temperature is on the high side, the equipment is working too hard and could fail earlier than expected. If the temperature is on the low side, the equipment is under-performing.
Installing a power or current sensor on your compressor provides data on power consumption Using the data from the power and the flow sensors, you can determine the health of your compressor. When combined, these two data points allow you to calculate the cost per unit ($/cf) of compressed air. Analyzing the cost per unit determines if your compressor has performance problems such as short-cycling, faulty controls, or unregulated spikes. This also determines if your compressor is oversized for your application.
Compressed air is a costly, but vital utility in your facility. Monitoring your compressed air system’s performance identifies problem areas. By knowing these problems, you can make educated system improvements. Monitoring your system after making improvements ensures your investment is protected from reverting back to an under-performing system.
For assistance with a site survey, turn to Parker Transair. Our team of trained professionals will visit your facility and help you develop the monitoring solution that fits your needs.
For a ready to implement monitoring solution, turn to Parker’s Transair Condition Monitoring. Our sensors and cloud-based software collects the data and alerts you to sudden shifts in performance. For an out of the box solution, we offer the Transair Condition Monitoring Starter Kit. The Starter Kit provides the basics for monitoring your compressed air system. The kit includes 5 pressure sensors, 1 humidity sensor, 1 signal repeater, and 1 cellular collection server.
For more information on Transair Condition Monitoring, please visit our website.
This post was contributed by Keith Harger, applications engineer, Parker Fluid System Connectors Division.
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